It’s almost 40 meters long and can prowl the world’s ocean for months at a time--all by itself without a human on board.

The drone, which is officially called an Anti-Submarine Warfare Continuous Trail Unmanned Vessel, or ACTUV, is the largest unmanned surface vehicle ever built.

Starting this April, the drone, which was developed by the Defense Advanced Research Projects Agency (DARPA), will begin an 18-month period of sea trials to see how it performs in real-world conditions.

The sea trials will be overseen by the U.S. Navy, and in the future, the drone could be used for reconnaissance, such as tracking enemy submarines and for resupplying troops around the world. It reportedly can operate for between 60 and 90 days all by itself.

According to Fox News, the drone will have a kind of technological logic that would allow it to predict the behavior of enemy vessels. The logic could also allow the ACTUV to outmaneuver potential threats.

“Imagine an unmanned surface vessel following all the laws of the sea on its own and operating with manned surface and unmanned underwater vehicles,” said DARPA deputy director, Steve Walker, at a press conference earlier this month.